Mercedes-Benz has come in for a lot of criticism over the twin-MPVs B-class and its larger sibling R-class. ‘Why make these cars?’ is the question often asked.

Two reasons: to capture affluent family buyers and to help reduce dependency on the C-class by entering new niches.

Mercedes dealers have sold 1,000 R-class units in the six months since it went on sale (April). Next year they are likely to be doubling these volumes at least.

R-class starts at £40,020 for the 3.0-litre R320 CDI diesel, rising to £51,535 for the R500 sport. Both are long-wheelbase – now the standard for the UK. Add in the extras, though, and the price starts to rocket.

Test car options on our R320 include the Comand entertainment and navigation system, six-disc CD changer, privacy glass (good for shielding the family from the glare of the sun, but makes reverse parking at night a real problem), and hands-free telephone wiring. On the road at £47,430.

For dealers the profit opportunity from the upsell is excellent; margins from the R-class are healthy and discounting is minimal.

Positives? Six individual seats, good luggage space and impressive engines: the 3.0-litre diesel on test has bags of power. On the downside, it returned just 25mpg during a 600-mile week and it’s hard to justify a near £50k people carrier.

Price: £42,970 (£47,430 on test)
Engine: 3.0-litre 224bhp diesel
Performance: 0-62mph 8.8sec, top speed 134mph
Efficiency: 30.4mpg combined, 246g/km CO2
CAP RV: £18,325 (48%)
Rivals: Audi Q7, Volvo XC90, BMW X5, Porsche Cayenne
Strengths: Space, comfort, margins
Weakness: Ugly face, options raise prices
Opportunity: Capture affluent families
Threat: Do affluent families want MPVs?
USP: MPV goes upmarket